Search results

  1. audioguru2

    [help] Getting pure DC current

    What frequency? A filter capacitor will reduce it if the frequency isn't too low. What current? AA cells won't supply much current. What battery chemistry? Carbon-zinc and "heavy-duty" cells are lousy. Fresh alkaline cells have an internal resistance totalling 1 ohm so 1A will drop 1V. As they...
  2. audioguru2

    Digital radar speedometer

    Our "Digital Radar Speedometer" project is titled wrong. It doesn't use radar, it uses a laser. I don't think it works because its photodiode is backwards and doesn't have an amplifier. The radar circuits might work. Try them.
  3. audioguru2

    100W Amplifier Help

    Your "new" amp gives exactly the same output power as the original circuit. Its 80V total supply voltage makes about 70Vp-p across the speaker at full output. 70Vp-p is 24.75V RMS. 24.75V RMS across an 8 ohm speaker is 76.6W. If a 4 ohm speaker could be used then the amp's power would be about...
  4. audioguru2

    Digital radar speedometer

    You can save anything on your monitor's screen by pressing the "Prt Scrn" button on the keyboard's upper row. I paste it into MS Paint and crop it and save it as a PNG file. Like this one: I didn't know that the radar receiver is just a diode and an audio transistor inside the transmitter...
  5. audioguru2

    relay question

    Yes, some relays have a polarized coil. They also have a magnet inside to make them more sensitive. Why not look at the datasheet for your relay and learn everything about it. Then look at the catalog of a huge supplier and see all the different kinds of relays.
  6. audioguru2

    0-30 Vdc Stabilized Power Supply

    A 24V transformer has a peak voltage of 34V. The rectifier bridge will drop about 2V at full output. The two darlington-connected output transistors, R15, R7 and U2 will drop about 8V at full output leaving about 24VDC for max output. The transformer's peak voltage of 34V will have an average...
  7. audioguru2

    Digital radar speedometer

    Why don't you attach the schematic for the laser receiver circuit? Your 1st link has Google Book Search asking for me to login. Then it says I have the wrong password! Your 2nd link shows a display schematic without a receiver schematic. Attached is the display's schematic that I saved:
  8. audioguru2

    audioguru fm transmitter

    What are you talking about? A resistor from the transistor's collector to its base makes NEGATIVE FEEDBACK which reduces voltage gain. Add another transistor or use an opamp if you want more audio gain.
  9. audioguru2

    Digital radar speedometer

    You attached the PDF file for the Ramsey radar display unit, but it doesn't have the receiver's schematic. I am waiting for you to attach the schematic for the stuff you linked to. I can't open the link. The output level from a dimmly lighted photodiode is extremely low. I get most datasheets...
  10. audioguru2

    Convert 0-30V 3A PSU to 5A or more

    Then U2 must be driving a short. What control? Did you make the original project or the fixed and improved one? Did you substitute any parts?
  11. audioguru2

    Digital radar speedometer

    74LS is too slow for this circuit.
  12. audioguru2

    Digital radar speedometer

    Radar? Radar uses radio waves. I thought you want to use a laser diode transmitter and a photodiode receiver.
  13. audioguru2

    Audio Guru FM TX

  14. audioguru2

    audioguru fm transmitter

    My transmitter's mic is sensistive enough to pickup voices in a room where people are about 4m away. Enclosed in an AC jack it might not be sensitive enough. Hfe (current gain) has nothing to do with a transistor's voltage gain. Since your collector resistor's value is half then the voltage gain...
  15. audioguru2

    Digital radar speedometer

    Why not just attach the schematic here, instead of having everyone go over to Google and log in there to see it? I can't see the schematic in Google's Book Search!
  16. audioguru2

    Veronica PLL

    L2 is the main tuning coil so it better be made correctly. It is too bad that its consruction or value isn't given. The kit will include the coil. That transmitter doesn't have pre-emphasis (treble boost like FM radio stations) so it won't sound good. Its optional stereo encoder might have...
  17. audioguru2

    Convert 0-30V 3A PSU to 5A or more

    Does opamp U2 get hot? Is it an OPA445AP high voltage opamp? Is U2's output voltage higher than it should be? Is the project's output voltage too low? Then something is shorting the project's output to 0V and U2 is straining to make the voltage higher, making a high current in R15.
  18. audioguru2

    HELP - resistors and dip-switch

    Which circuit? Did you try the circuit I fixed? I have a DC motor speed control circuit using PWM that works perfectly. I use a dual opamp as an integrator and schmitt trigger to make a triangle wave and use another opamp as a comparator of the triangle wave to the DC setting of a pot like in...
  19. audioguru2

    Variable Capacitor

    Then you have shorted the variable capacitor with the wire. Yes. Yes. If you want their total capacitance of 220pF then connect them in parallel. Connect A to O and to the circuit and connect G to ground in the circuit.
  20. audioguru2

    500W 12v to 220v Inverter

    Hi Doron, A 2N3055 transistor will reach its absolute max internal temp and can dissipate 115W only if it has a PERFECT heatsink that is impossible to have. The heatsink gets hot because it isn't isn't a PERFECT heat radiator. When the heatsink gets hot then you must reduce the power in the...
Top